Methods and apparatus of stabilizing a valve positioner when testing a solenoid valve are disclosed. An example apparatus includes a solenoid valve and a valve positioner fluidly and communicatively coupled to the solenoid valve. The valve positioner is to be set in a pressure control state prior to conducting a test of the solenoid valve. The valve positioner is to detect a pressure change across the solenoid valve caused by the solenoid valve transitioning from a first state to a second state and transition the valve positioner from the pressure control state to a saturated state upon detecting the pressure change. The full supply pressure is to stabilize the valve positioner to conduct the test of the solenoid valve. The valve positioner is to maintain the saturated state until the pressure across the solenoid valve returns to the predetermined initial value.